There are many applications known in which documents are fed along a paper path and then collated for further processing. Generally, the documents must be properly aligned when the collation is formed before further processing, such as stitching or insertion into an envelope, can be performed. In some applications, such as, for example, photocopying machines, the collation is formed and then stitched at a stacking area. Typically, stitching is done either at the leading edge or at the trailing edge of a collation. In either case the collation is stopped adjacent to the stitching mechanism and stitched. The formation and processing of stitching collations can be carried out at high processing speeds where large number of collations are stitched, for example, at speeds of 20,000 stitched collations per hour.
Stitcher systems are known in the art and are available in paper handling systems for a variety of applications in which stapling of documents is required. Stitcher systems employ a continuous wire moved from a spool into a stitcher mechanism, where a suitable length of wire is cut and then used to form a stitch for a collation of documents. The stitch may be bent into the form of an open rectangle or U-shape prior to further bending at the time of clinching (e.g., closing the stitch to secure the collation). The open rectangle consists of a two vertical legs and a substantially perpendicular leg connecting one end of each of the two vertical legs to form the open rectangle. Various wire bending shapes may be employed.
Depending on the orientation of the stitcher mechanism and its position in relation to the collation to be stitched, the open end of the formed rectangle or U-shape may have an orientation extending downwardly from the top side of the collation (a top stitcher) or upwardly from the bottom side of the collation (a bottom stitcher). The open end of the stitch is driven through the collation and, after clinching, the stitch may be in the form of a rectangle that is almost closed or fully closed on the bottom or the top of the collation, as the case may be. In such case the two vertical legs are clinched somewhere between their ends so that they face each other and form a substantially closed rectangle and secure the collation together by the formed stitch. The height of the stitch is the difference between the top side and the bent sections of the two legs.